a.h - Assistant Professor, Department of Civil Engineering, Shiraz Branch, Islamic Azad University, Shiraz, Iran
h - Master of Science Student in Geotechnical Engineering, Estahban Branch, Islamic Azad University, Estahban, Iran
f - Master of Science Student in Geotechnical Engineering, International Shiraz University, Shiraz, Iran

The present paper investigates the behaviour of circular shallow footings on soft clayey soils with skirted and non-skirted sand piles. The main goal of this study is to evaluate the settlement and bearing capacity of a circular foundation, which is placed on a soft clay layer, based on a sandy soil layer. Different piles with varying length to clay layer thickness ratios ranging from 0.25 to 1 were modelled experimentally, both with and without skirt. The effects of using a steel skirt and the length to clay layer thickness ratio of the piles, compared to case in which the footing is placed on a pile without any skirt, and in the case of a shallow foundation without piles, were also investigated in this study. The results indicate that the use of skirted piles can affect the load settlement curves and increase the bearing capacity. By increasing the ratio of pile length to clay thickness, the bearing capacity of the shallow foundation will be increased and the corresponding settlement will be decreased. Therefore, the bearing capacity failure mechanism of a footing resting on soft clay can be modified from the punching failure to the general shear failure at the tip of the confined replaced sand column

Skirted pile, Bearing capacity, Circular footing, Soft clayey Soil, Experimental study.